I could centralize you could centralize he could centralize we could centralize you could centralize they could centralize
V-ing form
I could be centralizing you could be centralizing he could be centralizing we could be centralizing you could be centralizing they could be centralizing
Perfect
I could have centralized you could have centralized he could have centralized we could have centralized you could have centralized they could have centralized
V-ing perfect
I could have been centralizing you could have been centralizing he could have been centralizing we could have been centralizing you could have been centralizing they could have been centralizing
Negation
Simple form
I couldn't centralize you couldn't centralize he couldn't centralize we couldn't centralize you couldn't centralize they couldn't centralize
V-ing form
I couldn't be centralizing you couldn't be centralizing he couldn't be centralizing we couldn't be centralizing you couldn't be centralizing they couldn't be centralizing
Perfect
I couldn't have centralized you couldn't have centralized he couldn't have centralized we couldn't have centralized you couldn't have centralized they couldn't have centralized
V-ing perfect
I couldn't have been centralizing you couldn't have been centralizing he couldn't have been centralizing we couldn't have been centralizing you couldn't have been centralizing they couldn't have been centralizing
Interrogative form
Simple form
could I centralize? could you centralize? could he centralize? could we centralize? could you centralize? could they centralize?
V-ing form
could I be centralizing? could you be centralizing? could he be centralizing? could we be centralizing? could you be centralizing? could they be centralizing?
Perfect
could I have centralized? could you have centralized? could he have centralized? could we have centralized? could you have centralized? could they have centralized?
V-ing perfect
could I have been centralizing? could you have been centralizing? could he have been centralizing? could we have been centralizing? could you have been centralizing? could they have been centralizing?
Interro-negative form
Simple form
couldn't I centralize? couldn't you centralize? couldn't he centralize? couldn't we centralize? couldn't you centralize? couldn't they centralize?
V-ing form
couldn't I be centralizing? couldn't you be centralizing? couldn't he be centralizing? couldn't we be centralizing? couldn't you be centralizing? couldn't they be centralizing?
Perfect
couldn't I have centralized? couldn't you have centralized? couldn't he have centralized? couldn't we have centralized? couldn't you have centralized? couldn't they have centralized?
V-ing perfect
couldn't I have been centralizing? couldn't you have been centralizing? couldn't he have been centralizing? couldn't we have been centralizing? couldn't you have been centralizing? couldn't they have been centralizing?